- 2 cups light rye flour (such as Bob's Red Mill®)
- 2 cups bread flour
- 1/4 cup buttermilk
- 2 tablespoons caraway seeds
- 1 1/2 tablespoons vital wheat gluten (optional)
- 2 teaspoons flaked kosher salt, crushed
- 1 3/4 cups warm water
- 2 teaspoons white sugar
- 3/8 teaspoon active dry yeast
- Mix rye flour, bread flour, buttermilk, caraway seeds, vital wheat gluten, and kosher salt together in a very large bowl.
- Combine water, sugar, and yeast in a bowl until yeast softens and begins to form a creamy foam, about 5 minutes. Stir yeast mixture into flour mixture until well mixed and caraway seeds are evenly distributed. Cover bowl with plastic wrap and let sit for 18 hours.
- Transfer dough to a heavily floured work surface. It will be somewhat elongated, so take the right and left sides and fold them into the middle. Turn dough over and gently use a spatula to tuck corners under; cover with plastic wrap for 15 minutes. Remove plastic wrap, dust dough with flour, and make shallow cuts in the top for full bloom.
- Place a Dutch oven in the oven and preheat oven to 500 degrees F (260 degrees C).
- Carefully place dough in the Dutch oven, cover immediately, reduce oven temperature to 460 degrees F (238 degrees C), and bake until bread is cooked through, 30 to 35 minutes. Carefully transfer bread from the Dutch oven to the oven rack and bake for 5 minutes more.